In June last year I broke the derailleur hanger on my 2012 Ribble 7005 Ultralite Racing. A modestly priced alu road bike.
The model was discontinued in 2016 and Ribble no longer sold replacement hangers. It is an OEM design and no one else sold them. If I couldn’t replace it the bike was a write off, and with qr wheels, rim brakes and a straight steerer the components were a write off too. A major bummer having rebuilt the wheels in spring.
So I went to work.
A correspondence of over 67 emails ensued between myself and one customer services worker, two customer account managers, the head of purchasing and latterly the CEO of Ribble himself. 8 months later I have a replacement hanger and they are now restocked on the Ribble website.
I can’t say that I’m happy or impressed with how Ribble have handled the whole thing but by digging my heels in I’ve managed to rescue a potentially useless frame. The Ribble CEO Andy Smallwood had also said he has instigated a review of the spare parts back catalogue to ensure this won’t happen to anyone again. If that’s really true, I’m pretty pleased with my work.

Good work.

I always assumed mech hangers were something designers picked from a catalogue.

Well done Luke. The fact you don't have to order them from Germany with the package arriving from China (like my Canyon of late) or, that you can't ask them at the point of sale, to swap out the stem for a shorter one (my Canyon of late and I still haven't sent back the old stem which they'd replaced post delivery of the frame cos it would've cost me ).

Well done Ribble too for not blocking your emails and you having to take it to Twitter

The Ribble CEO Andy Smallwood had also said he has instigated a review of the spare parts back catalogue to ensure this won’t happen to anyone again. If that’s really true, I’m pretty pleased with my work.

Yes..

I always assumed mech hangers were something designers picked from a catalogue.

If the dropout is an open mold then yes, or if you design your own dropout you'd use existing hanger specs where possible. Then you order stock with the bikes and stock-control them / re-order as needed, or should.